67 
The  colour  of  the  worm  is  greenish  yellow,  except  on  the  clitellum, 
which  is  whitish  and  very  noticeable.  Through  the  transparent  body- 
wall  the  prostata-glands  and  ventral  nerve-cord  are  visible. 
The  prostomium  is  inverted  and  could  not  be  recognized. 
The  male  generative  pore  is  situated  upon  a  papilla;  a  depressed 
median  ventral  area  exists  upon  segment  XVII,  XVIII  and  XIX, 
bounded  laterally  by  a  glandular  ridge,  in  the  middle  of  which  the 
papilla  of  the  male  pore  is  situated.  A  single  female  pore  on  an  ob- 
vious glandular  area.  A  pair  of  papillae  upon  the  anterior  margin  of 
segment  VII,  on  a  short  distance  from  the  ventral  median  line. 
About  44  setae,  arranged  in  a  continuous  row,  in  the  segments 
in  front  of  and  behind  the  clitellum;  this  number  increazes  forwards, 
so  that  upon  segment  VII  60  bristles  are  to  be  found.  In  the  anterior 
segments  however  it  decreazes  gradually;  on  the  clitellum  no  setae 
were  observed ,  except  upon  segment  XVI ,  where  there  occur  five  on 
each  side  of  the  ventral  median  line. 
The  intestinal  canal  resembles  that  of  other  Perichaetae;  the 
pharynx  is  covered  with  glands  and  a  narrow  oesophagus  occupies 
segment  VI  and  VII ,  widening  out  in  segment  VIII ,  where  it  passes 
into  the  gizzard ,  situated  in  segment  IX  and  X.  The  intestinal  coeca 
are  short  and  obtuse. 
There  is  one  pair  of  spermathecae  in  segment  VII;  they  con- 
sist (Pl.  Ill,  fig.  27)  of  a  long  and  tubular  pouch,  somewhat  dilated  at 
its  internal  extremity,  and  a  slender  diverticulum,  that  measures  about 
twothirds  of  the  length  of  the  main  pouch ,  and  consists  of  a  small  sac 
with  a  long  and  narrow  excretory  duct.  The  pores  of  both  spermathecae 
are  probably  situated  upon  the  papillae  of  segment  VII.  The  prostata 
is  a  well-developed  gland ,  opening  externally  by  a  S-like  bended  duct, 
without  muscular  bulbus.  The  nephridia  are  diffuse. 
As  far  as  I  know  of,  this  is  the  smallest  Perichaeta-species  hitherto 
described;  the  examples  however  appear  to  be  in  a  state  of  sexual 
maturity. 
Three  Perichaeta-species ,  possessing  only  a  single  pair  of  sperma- 
thecae, are  already  described  from  the  Malayan  region,  viz.  P.  quadra- 
genaria  Perr. *),  P.  sangirensis  Mich. 2)  and  P.  racemosa  Rosa  3).  The 
1)  Nouv.  Arch.  T.  VIII,  p.  122,  Pl.  IV,  fig.  69. 
2)  Jahrb.  Hamb.  Wissensch.  Anstalten,  T.  VIII,  1891,  p.  36. 
3)  Ann,  K.  K.  Naturh.  Hofmuseums,  T.  VI,  1891,  p.  399,  Pl.  XIV,  fig.  8. 
